Improvement in elastic cushions for millstones



S. KEITH. Elastic Cushion fr Mllstones.

No. 218,884. Patented Aug. 26,1879.

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UNITED STATEs PATENT OEEICE.

SQUIRE KEITH, OF SILVER GREEK, NEW YORK, ASSIGNOR OF ONE-HALF HIS RIGHT TO ALBERT H. SPAULDING, OF SAME PLAGE.

IMPROVEMENT IN ELASTIC CUSHIONS FOR MILLSTONES.

Specification forming part of Letters Patent No. 218,884, dated August 2G, 1879; application .filed May 23, 1879.

To all whom it may concern.-

, Be it known that l, Soulan KEITH, or' Silver Creek, in the county of Chautauqua and State oi" New York, have invented certain new and usei'ul Iml'irovements in Elastic Cushions i'or Millstones; and I do hereby declare that the following is a full, clear, and exact description of the invention, which will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters of reference marked thereon, which form apart of this speciiication.

Figure l is a perspective view ot' an elastic cushion or bed for the stationary stone of a griiuling-mill, and ofthe in echauism connected therewith. Fig. 2 is an elevation ot' aportion ot' a foundation for the stone to rest upon, the elastic tube or cushion, and the bed-stone, the parts being in position for operation, and Fig. 3 shows the saine parts, with the addition of adjusting-screws andan adjustable plate for supporting the yielding tube orcushion, whereby the face oi' the bed-stone may be adjusted or trammed to cause it to correspond with the face et' the revolving' stone or the position of the spindle upon which it rests.

This invention relates to an apparatus upon which the stationary stone 'oi' a grinding-mill is to be placed, its object being to provide a means whereby the stationary or bed stone may be made to retain a proper relation to the revolving stone, even though said revolving stone may not be exactly balanced, or in case the unequal wearing of any of the parts should produce a wabbling motion thereof; and it consists in combining, with the stationary or bed stone, an elastic tube or cushion, to be placed between the stationary stone of a grindingmill and its foundation, or between said stone and an adjustable plate supported by such foundation, and filled with compressed air or other gaseous substance, so that iu the event of an undue amount of pressure bein g brought to bear upon any part ot the stationary stone by the imperfect workingof the revolving' stone said stationary one will be capable of yielding or retreating to such an extent as not to cause any considerable additional pressure at the point or points where such pressure would otherwise be applied, by which means the stones are at all times maintained in their proper relations to cach other, and it further consists in combining, with an elastic tube or cushion for supporting` the stationary stone of a grinding-mill, an air-pump or other suitable air or gas ibrcing device for supplying` air or gas to said tube or cushion and for controlling the pressure within said tube or cushion, and in certain other combinations, as will be more i'ully described hereinafter.

It is an ascertained fact that when the stationary stone oi" a mill for grinding grain, and especially those used for making iiour, is made to rest upon an unyielding foundation or support it is liable to have a greater amount ot pressure brought to bear upon parts of it than is applied to other portions at the same time, in consequence of a wabbling motion of the revolving stone, duc to an uneven balancing' thereof, or in consequence oi' an unequal wearing of the revolving stone or its supporting parts and it is also well known that under the circumstances last above recited it is impossible to make an even grade of iiour, as the meal which happens to be between the points where the greatest amount of pressure is brought to bear, or between the points where the stones come in contact or the most nearly in contact, will be reduced te a condition of greater neness than will other portions which are between points where less pressure is put upon the stationary stone.

My improvement isdesigncd to remedy the above-recited difficulty; and to this end, in applying it practically, I provide any suitable foundation, A, for the stationary stone when it is the lower one ofthe two, as shown in Fig. 2 of the drawings. Upon this foundation there is placed an elastic tube or cushion, B, of rubber, leather, or other suitable and sufficiently stron g material to sustain the required pressure; or said cushion may rest upon an adjustable plate supported upon leveling' screws or wedges arranged in a port-ion of the foundation, as shown in Fig. 3, by which means the bed-stone may be brought into tram with the spindle ot" the revolving stone and with the tace thereof. This cushion may be made cylindrical in forinin cross-section, or it may be ot any other suitable shape, as, for instance, it may be oblong or it may be of such form as to extend inward nearly to the eye 'of the stone, and yet not be of proportionately greater vertical depth than the one shown in the drawings. Whatever the form of the cross-section this cushion or tube should be of a diameter not greater than that of the stationary stone, and should be so placed upon the foundation that the bed or stationary stone O may be made to rest thereon, the meal, as it is ground being takenaway by anyof the well-known methods.

In order that this tube or cushion may be supplied-with air or other forms of gas, its ends are united by a T-shaped coupling, D, thed-V ameter of which is less than the vertical depth of the tube or cushion, in order that it may not prevent the retreating of the stone at the point where it is placed. The tube or cushion is supplied with nuts for connecting its ends to the T-piece, as shown in Fig. 1.

For supplying the tube or cushion B with air or other form of gas, and maintaining the requisite pressure therein, a pump, E, or other suitable compressing device is provided. Thisdevice may be a single-acting air-pump, such as is shown, and be operated by-hand, or it may be of any other of the well-known forms .of air or gas compressors, and it may be driven by the same motor which drives the stones of the mill, or by a separate motor, as found most convenient. This pump or air-forcingdevice is supplied with the usual induction andeduction valves E1 and E2, and between the eduction -valve El and the hose or pipe F, which leads thecompressed air or gas to the tube or cushion B, there is placeda safety-valve, G, which is 'suppliedwith a weight, G', and with a lever, which may, if desirable, be graduated in such a manner as to indicate the pressure maintained within the tube or cushion B. Thel object had in view in providing this safetyvalve is to affordy relief to the tube or cushion when the pressure is up to the required'point, and thus prevent the possibility of burstingit, and this will be found of great utility when the compressing mechanismis driven by power,

as at such times the valve maybe setto retaink within the pipe and the cushion just the required pressure, and thus any surplus that mayl obtain in consequence of any increase` in the speed of the motor will pass olf without injury to any of the parts.

For the purpose of still further indicating the pressure within the tube or cushion there is shown apressure-gage, H, which is connected to the safety-valve below or within its point of discharge. By the use of a gage of this character the pressure is at all times indicated, and it may be found useful when the pressure is so low as not to raise .the safety-valve. It is not, however, essential to the practical working of the other parts of the device.

Having thusy described my invention, what I claim, and desire to secure by Letters Patent, is-

1. In combination with the stationary bedstone of a grinding-mill, an elastic tube or cushion in which air or other gaseous substance.

is maintained under pressure, for the purpose of lsupporting the stone, substantially as set forth.

2. The combination of a pump or equivalent air or gas compressing device, an elastic tube or cushionfor supporting the stationary stone of a grinding-mill, and an intermediate pipe or hose for conveying the compressed air or gas from the pump to the tube or cushion, substantially as described. 1

3. The combination of the tube or cushion B, the pump E, connecting pipe orhose F,

Vsafety-valve Gr, and pressuregage H, when constructed andy operating substantially as 'and for the purpose set forth.

4. The combination-of the elasticfor yield- 'ing tubeor cushion B with the pump E or other equivalent air-compressing device, the connectingvpipe or hose F, stationary stone C, and a bed-plate for the support of said stone, all substan tially-as-set forth. f

In testimonythat "I claim the foregoing as my own I afx myvsignatu're in presence of two witnesses.

SQUIRE Kamin.` 

